From: Willy Tarreau <w@1wt.eu>
Date: Fri, 23 May 2014 14:36:56 +0000 (+0200)
Subject: CONTRIB: halog: avoid calling time/localtime/mktime for each line
X-Git-Tag: v1.5-dev26~5
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=9f66aa9cc40d5cc5405b23ddc100068474252fb4;p=thirdparty%2Fhaproxy.git

CONTRIB: halog: avoid calling time/localtime/mktime for each line

The last commit provides time-based filtering. Unfortunately, it wastes
90% of the time calling the expensive time()/localtime()/mktime()
functions.

This patch does 3 things :
  - call time()/localtime() only once to initialize the correct
    struct timeinfo ;

  - call mktime() only when the time has changed regardless of
    the current second.

  - manually add the current second to the cached result.

Doing just this is enough to multiply the parsing speed by 8.
---

diff --git a/contrib/halog/halog.c b/contrib/halog/halog.c
index 364bf90aed..c686de1e38 100644
--- a/contrib/halog/halog.c
+++ b/contrib/halog/halog.c
@@ -537,7 +537,8 @@ int convert_date_to_timestamp(const char *field)
 	unsigned char c;
 	const char *b, *e;
 	time_t rawtime;
-	struct tm * timeinfo;
+	static struct tm * timeinfo;
+	static int last_res;
 
 	d = mo = y = h = m = s = 0;
 	e = field;
@@ -651,17 +652,28 @@ int convert_date_to_timestamp(const char *field)
 		s = s * 10 + c;
 	}
 
-	time(&rawtime);
-	timeinfo = localtime(&rawtime);
+	if (likely(timeinfo)) {
+		if (timeinfo->tm_min == m &&
+		    timeinfo->tm_hour == h &&
+		    timeinfo->tm_mday == d &&
+		    timeinfo->tm_mon == mo - 1 &&
+		    timeinfo->tm_year == y - 1900)
+			return last_res + s;
+	}
+	else {
+		time(&rawtime);
+		timeinfo = localtime(&rawtime);
+	}
 
-	timeinfo->tm_sec = s;
+	timeinfo->tm_sec = 0;
 	timeinfo->tm_min = m;
 	timeinfo->tm_hour = h;
 	timeinfo->tm_mday = d;
 	timeinfo->tm_mon = mo - 1;
 	timeinfo->tm_year = y - 1900;
+	last_res = mktime(timeinfo);
 
-	return mktime(timeinfo);
+	return last_res + s;
  out_err:
 	return -1;
 }